leetcode

Daily Problem

2 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/ Problems/2097.cpp b/ Problems/2097.cpp

@@ -0,0 +1,39 @@

class Solution {

public:

vector<vector<int>> validArrangement(const vector<vector<int>> &pairs) const {

unordered_map<int, int> in, out, count;

unordered_map<int, vector<int>> adj;

for (const auto &p : pairs) {

adj[p[0]].push_back(p[1]);

out[p[0]]++, in[p[1]]++;

}

int start = pairs[0][0];

for (const auto &[v, _] : adj) {

if (out[v] - in[v] != 1) continue;

start = v;

break;

}

stack<int> st;

vector<int> res;

for (st.push(start); !st.empty();) {

const int crnt = st.top();

if (count[crnt] != size(adj[crnt])) {

st.push(adj[crnt][count[crnt]++]);

} else {

res.push_back(crnt);

st.pop();

}

}

vector<vector<int>> pair_res;

for (int i = size(res) - 2; i >= 0; i--) {

pair_res.push_back({res[i + 1], res[i]});

}

return pair_res;

}

};

diff --git a/ README.md b/ README.md

@@ -1192,6 +1192,7 @@ reference and a base for solving problems. | 2092 | Hard | [Find All People With Secret](Problems/2092.cpp) | | 2095 | Medium | [Delete the Middle Node of a Linked List](Problems/2095.cpp) | | 2096 | Medium | [Step-By-Step Directions From a Binary Tree Node to Another](Problems/2096.cpp) |

| 2097 | Hard | [Valid Arrangement of Pairs](Problems/2097.cpp) |

| 2100 | Medium | [Find Good Days to Rob the Bank](Problems/2100.cpp) | | 2101 | Medium | [Detonate the Maximum Bombs](Problems/2101.cpp) | | 2104 | Medium | [Sum of Subarray Ranges](Problems/2104.cpp) |